There is good indirect evidence suggesting that cAMP (adenosine 3' ,5'-monophosphate) mediates the induction of protein synthesis at the transcriptional level. cAMP regulation of transcription conceivably is mediated through a mechanism involving nuclear translocation of cytoplasmic cAMP-dependent protein kinase, phosphorylative modification of nuclear regulatory proteins resulting in altered DNA template activity, altered RNA polymerase activity, and altered RNA synthesis, that is the synthesis of the specific mRNA which codes for the induction protein. The proposed studies are aimed at defining (a) the precise mechanism of nuclear translocation of protein kinase by biochemical and immunochemical methods; (b) the role of nuclear translocation of cytoplasmic protein kinase in the phosphorylative modification of nuclear nonhistone proteins; (c) the role of protein kinase translocation in the synthesis of specific mRNA.